ARM: rmobile: Handle R8A7796 r1.1 in the PRR code

The R8A7796 r1.1 reports itself as r2.0 , add quirk into the
PRR code to fix this report.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>